A Phase I Study of Systemic Gene Therapy With SGT-94 in Patients With Solid Tumors

RB94, a tumor suppressor gene, is a modified form of the retinoblastoma gene, RB110. RB94 has shown enhanced tumor suppressor and tumor cell killing activity compared to RB110 in all tumor cell types studied to date, including bladder cancer cell lines. Moreover, RB94 has shown no toxicity to any normal human cells tested. SGT-94,the agent being tested, is a systemically administered complex composed of the RB94 gene (plasmid DNA)encapsulated in a liposome that is targeted to tumor cells by means of an anti-transferrin receptor single chain antibody fragment (TfRscFv)attached to the outside of the liposome. Pre-clinical in vivo efficacy studies have indicated that SGT-94, when systemically administered, preferentially targets tumor cells and efficiently transfects them. This results in cancer cell death via mechanisms that are unique for RB94 and also increases the tumor's response to conventional radiation and chemotherapy. This Phase I study is designed to evaluate the safety of SGT-94 and to establish a practically attainable and/or tolerable dose of this anti-cancer agent for use in further clinical trials. Additionally, evidence of RB94 expression within tumor tissue after systemic administration of SGT-94 will be sought, and clinically observable anti-cancer effects in patients will be documented. Enrollment will be targeted to individuals with "RB negative" tumors, i.e. tumors in which there is no staining for RB protein by immunohistochemistry (IHC). Preference will be given to patients with tumors in a location amenable to biopsy following treatment with SGT-94. This would include the prostate, bladder, superficial lymph nodes and any mass suitable for fine needle aspiration under CT or ultrasound guidance, or any lesion reachable by endoscopy.